Auto chord device

ABSTRACT

Apparatus for playing chords on a guitar which enables a rapid change between chord positions, including the major, minor, and dominant seventh chords of two keys separated by five half-tones. The apparatus comprises a chording device with levers for changing between the major, minor and dominant seventh chords of one key. The chording device is shiftable laterally, and it includes cams which alter the positions at which the guitar strings are depressed when a lateral shift occurs to establish the corresponding chord in the other key.

United States Patent Inventors Richard S. Chang Gardena; Marshall B. Pearhnan, Los Angeles; John W. Ryan, Los Angeles; George W. Sioles, Palos Verdes Estates, Calif. Appl. No. 784,832 Filed Dec. 18, 1968 Patented Mar. 9, 1971 Assignee Mattel, Inc.

Hawthorne, Calif.

AUTO CHORD DEVICE 11 Claims, 16 Drawing Figs.

U.S.Cl.., 84/317, 84/473 Int. Cl Gl0d 3/00, 60% 15/02 Field ofSearch 84/317, "314, 315, 473, 443,416, 480

[5 6 References Cited UNITED STATES PATENTS 357,168 2/1887 Barnwell 84/314 2,746,337 5/1956 Smit 84/317 2,798,398 7/1957 Hayes..,..,...., 84/317 2,824,479 2/1958 De Rosa 84/473X 3,422,717 1/1969 Roussel 84/317 Primary Examiner-Richard B. Wilkinson Assistant Examiner-John F. Gonzales Attorney-Seymour A. Scholnick ABSTRACT: Apparatus for playing chords on a guitar which enables a rapid change between chord positions, including the major, minor, and dominant seventh chords of two keys Patentd March 9, 1971 3 Sheets-Sheet 2 v N Q Y I I 0 MM a w v w m a z r .Pm a as .2. n mu MANN Kw? P A H AUTO CHORD DEVICE BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to chord forming apparatus for musical instruments.

2. Description of the Prior Art Guitars are commonly used in folk music to form chords for accompanying asinger. In much of this music, a melody can be accompanied by the sounding of chords in two families of chords that are separated by five semitones or half-tones, such as the families G and C, or E and A; A'family of chords comprises those chords whose common names contain the same letter; for example, the G major, G minor, and G dominant seventh chords are all in the G family of chords. (a letter followed by a sharp or flat such as G?- or G! is considered still another family designation). It is desirable to provide the major, minor and dominant seventh chords in each of these families that are spaced-by five half-tones in order to properly accompany the melody.

Many chording devices have been proposed, which contain levers for depressing groups of guitar strings to form major, minor and dominant'seventh chords in any family. However, these devices generally have required longitudinal shifting along the neck of the guitar to make any change to another chord family. Since a typical melody will require frequent changes between chord families separated by five half-tones, the chording devices had to be shifted along the guitar neck by five frets. This required substantialtime and effort, which interferred withthe uninterrupted play of music. In addition, when the chording device was shifted up by five half-tones, the .upper note of the chord was in a much higher pitch range, which often produced an undesirable effect.

SUMMARY OF THE INVENTION In accordance with the present invention, a simple chording mechanism is provided which facilitates the playing of closely related chords on guitars and similar instruments. The mechanism comprises a frame which can be moved to a desired fret position longitudinally along the guitar neck. A stop or fret assembly is mounted on the frame for lateral shifting to form chords in either of two families without moving the frame along the guitar. The fret assembly carries movable frets that are automatically moved against or away from the strings by cams on the frame when the assembly is shifted laterally.

In one embodiment of the invention, the frame has a bar which depresses all six guitar strings at one fret position. A laterally movable slide'is mounted on the frame, which has stops for depressing some of the guitar strings at fret positions above the bar. In a first lateral position of the slide, the stops forms a chord in one family such as E, while in the other lateral position it forms the corresponding chord in a family which is five half-tones higher, which in this case would be A.

The stops on the slide include a short bar stop that always depresses two strings, and a cam operated stop that can depress one string. When the assembly is in the first lateral position, the short bar stop depresses the fourth and fifth strings, while the cam operated stop is lifted from the strings, to produce a chord such as E minor. When the assembly is shifted to the second lateral position, the bar stop presses the third and fourth strings, while the cam-operated stop is pushed down to press on the second string, to produce the corresponding chord, A- minor. Two manually operated levers are also provided for operating additional stops, one of which changes the chords from minor to major in the same family, and the other from major to dominant seventh in the same family.

The frame slides along a track fixed to the side of the guitar. A chart is provided on the track to indicate the two chord families which are played for any position of the frame along the neck of the guitar. The chart can be shifted slightly to display other sets of families at each fret position, to aid in transposing.

The novel features of the invention are set forth with particularity in the appended claims. The invention will be best understood from the following description when read in conjunction with the accompanying drawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of chording apparatus constructed in accordance with the invention;

FIG. 2 is a side elevation view showing the chart portion of the apparatus of FIG. 1;

FIG. 3 is a sectional rear view taken on the line 3-3 of FIG.

FIG. 4 is a bottom elevation view'taken on the line 4-4 of FIG. 3;

FIG. 5 is a sectional side view taken on the line 5-5 of FIG.

FIG. 6 is a sectional rear view of the apparatus as shown in FIG. 3, but in a second lateral position;

FIG. 7 is a bottom elevation view of the apparatus as shown in FIG. 4, but in a second lateral position;

FIG: 8 is a diagram illustrating the fretting positions of the apparatus of FIG. 1 for forming an A minor chord on a conventionally tuned guitar;

FIG. 9 is a diagram illustrating the fretting position for forming an A major chord;

FIG. 10 is a diagram illustrating the fretting position for forming an A dominant seventh chord;

FIG. 11 is a diagram illustrating the fretting position for forming an E minor chord;

FIG. 12 is a diagram illustrating the fretting position for forming an E major chord;

FIG. 13 is a diagram illustrating the fretting position for forming an E dominant seventh chord;

FIG. 14 is a bottom perspective view of chording apparatus constructed in accordance with another embodiment of the invention;

FIG. 15 is a diagram illustrating the fretting position of the apparatus of FIG. 14 for forming an A augmented chord; and

FIG. 16 is a diagram illustrating the fretting position for forming an A diminished chord.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates the chording apparatus 10 which is mounted on a guitar 12. The guitar has a neck 14 with a series of frets l6 spaced longitudinally therealong and has six strings generally turned to the notes E, B, G, D, A, and E. The chording apparatus includes a guide 18 mounted on the side of the guitar neck nearest to the player, and a frame 20 which can move along the guide to any fret position on the guitar neck up to the body of the guitar. For any fret position of the frame, the chording apparatus can be used to form two groups of chords in either of two music chord families.

A scale or chart 22 which is mounted on the guide carries sets of key indications, such as the set E A" which shows through a window 24 in the guide. This indicates that with the frame in the fret position shown, the chording device can be used to form chords in the families E and A. A slide 21 mounted on the frame,'can be shifted laterally to change between the two chord'families, such as E and A. The slide carries two chording levers 26 and 28 which can be depressed to alter the chords in a given family. Thus, in the position shown in FIG. 1 where no levers are depressed, the apparatus forms the chord A minor. A lateral shift of the slide 21 in the direction of arrow 30 changes the chord to E minor. However, with the device in the A minor position, a change to A major is accomplished by merely depressing lever 26 while a change to A dominant seventh is accomplished by depressing both levers 26 and 28. In a similar manner, for the device in the E minor position, a change to E major or E dominant seventh is accomplished by depressing lever 26 or both levers 26 and 28, respectively.

In order to play a typical song, the musician moves the frame 20 to a fret position which is high or low enough to allow singing of the melody without strain. For example, this may be the fourth fret position such as is shown in FIG. 1, where chords in the families of E and A are formed. Generally, the melody can be successfully accompanied by merely using the E and A chords with an occasional change to the family of D.The latter change is accomplished by moving the frame down by two fret positions which, although it requires a small amount of time, is not excessively burdensome because it occurs only occasionally. The repeated shifts between the various E and A chords is accomplished by pushing laterally on a protuberance 32 which is part of the slide, to laterally shift the slide, and by depressing the levers 26 and 28, all of which can be accomplished quickly and with little effort.

FIGS. 8 through 13 illustrate the manner of forming chords on the guitar by the chording apparatus. A bar 34 is fixed to the frame depresses all six strings at the same initial fret position. The A minor chord of FIG. 8 is formed by first and second stops 36 and 38. The first stop 36 is positioned on the third and fourth strings (normally tuned to the notes G and D as indicated) at two higher fret positions than the bar. The second stop 38 is positioned on thesecond string (usually tuned to B) at one higher fret position than the bar. To shift to theE minor chord of FIG. 11, the first stop 36 is shifted laterally by one string to the position 36', while the second stop is lifted. As will be described below, the lateral shift of first stop 36 is accomplished by lateral shifting of the slide, while the lifting and depressing of second stop 38 is accomplished automatically when the slide is shifted.

In order to change from the A minor to the A major chord of FIG. 9, a third stop 40 is depressed, which is accomplished by depressing the first lever 26 (this also causes the second stop 38 to be depressed). To change from the A major to the E major chord of FIG. 12, the slide is shifted laterally while the first lever is held down. This causes the third stop 40 to be lifted, but allows the second stop 38 to remain depressed, at position 38". A change to the dominant seventh chords of FIGS. and I3 is accomplished by depressing the second lever 28, to lower a fourth stop member 42.

FIG. 4 is a bottom view of the frame and slide 21 in an unshifted position for playing the A chords in the manner described above. The slide is confined to lateral shifting with respect to the frame by a rod 44 fixed to the frame and engaged with a hole in the slide, and by various portions of the slide. A spring 46 disposed about the rod biases the slide toward the position shown in the FIG. The first stop 36, which covers two strings, is a short barlike protrusion which is fixed to the slide by screws 48. The second and third stop members 38 and 40 are small protrusions on opposite ends of a multiple stop member 50. The multiple stop member 50, which is in the form of a bar, is below a first chording lever 26, and a rod 52 connects them. The fourth stop member 42 is a button connected to the second chording lever 28.

The member 50 can perform several pivoting movements to form the appropriate chords. One of these is an automatic pivoting when none of the chord levers is depressed, to change from A minor to E minor when the slide is shifted laterally. The member 50 is pivotally mounted on the rod 52 for enabling the stop 38 to be pressed against a string or lifted away. A cam portion 54 of the frame pivots the member 50 to depress the stop 38 when the slide is in the unshifted position of FIG. 4. However, when the slide is shifted to the position of FIG. 7, the cam portion 54 allows the stop 38 to lift away from the strings. Thus, the stop 38 is depressed and released automatically when the slide is shifted, to form the A minor and E minor chords of FIGS. 8 and 11.

The multiple stop member 50 is also mounted so that when the first chording lever 26 is pressed, either the second stop 38 or the third stop 40 (plus the second stop) will move down. Thus, the apparatus will form either the A major or E major chords of FIGS. 9 and 12in accordance with the lateral position of the slide. To accomplish this a pivot end 56 is provided on the member 50, which is received under a ledge 58 of the frame when the slide is shifted to the position of FIG. 7, as also illustrated in FIG. 5. Then, when the first chording lever 26 is depressed, the ledge 58 serves as a pivot and the member 50 pivots about the end 56. This causes stop 38 (in the position 38') to be pressed on the strings while the third stop 40 remains in its lifted position. This produces the E major chord of FIG. 12. When the slide is returned to the position of FIG. 4, pressing of the first chording lever 26 presses down both stops 38 and 40, which yields the same effect as pressing down only stop 40, and the A major chord of FIG. 9 is formed.

FIGS. 3 and 6 also illustrate the chording apparatus in the two lateral positions of the slide. As shown, the multiple stop member 50 is biased upward by a spring 60 disposed about the rod 52. The upper end of the rod 52 is positioned immediately under the first chording lever 26. When the lever 26 is depressed, the rod 52 is pushed down. The member 50 is therefore depressed to press down both of the stops 38 and 40 when the slide is positioned as shown in FIG. 3, or to press down only to the stop 38 when the slide is in the shifted position of FIG. 6.

The mechanism for operating the fourth stop 42 is shown in greater detail in FIG. 5. The stop 42 is positioned at the end of a rod 62 which is biased up by a spring 64. When the second chording lever 28 is depressed, the rod 62 is pressed down. This depresses the stop 42 onto either the first or second strings, to form an A dominant seventh or E dominant seventh chord (when the first lever is also depressed). I The frame 20 is pivotally mounted on a bracket 66 that slides along the guide 18. The guide has an undercut slot that receives a slider bearing 68 on the bracket. The entire frame and bracket can be removed by sliding it off the end 70 of the guide. If it is desired to rapidly move the frame out of the way, this can be accomplished by pivoting it around the hinge 72, away from the guitar neck.

The guide has a slot 74 extending along its length for holding a chord chart 76. The chord chart has sets of chord family indications marked thereon, which-can be read through windows in the guitar such as window 24. The two chord family indications which show through one window are spaced five half-tones apart. As indicator mark 77 on the bracket shows which pair of chords will be played for a given position of the frame along the guitar neck. Thus, when the frame is in the position of FIG. 1, and it is desired to play a D chord, the musician can move the frame down by two fret positions to the position opposite window 25 where the letter D is showing. Where dots are showing instead of a letter, the chord is in a sharped or flatted family. For example, in FIG. I the two dots showing through window 27 indicate that the corresponding chords are 05 G5 (or B3 A:

In many situations it is desirable to transpose between different keys. For example, sheet music for the guitar may indicate that a C should be sounded at the beginning of a song, the music indicating various chords to be played at other parts of the melody. However, it may be found that this requires singing in too high or too low a pitch. This difficulty is remedied by starting the song with another chord such as E, which is four half-tones higher, and playing all other chords as though they were written four half-tones higher. A beginning musician may find great difficulty in rapidly choosing the proper chord as he plays. To eliminate this difficulty, the chart 76 is provided with additional sets of chord markings to facilitate transposing. The chart essentially enables the reheating of all chords.

As shown in FIG. 2, the chart 76 has three groups of notations, any one of which can show through the windows of the guide. Each group is four half-tones different from the adjacent group. For example, the group 78 which represents C and F chords is four half-tones higher than the group 88 which represents 6;: and C? chords, which in turn is four halftones higher than the group 82 which represents E and A chords.

The use of the movable chart can be appreciated by considering the situation where the music indicates that the first chord should be C, but it is found that C is too high while an E chord is just right. To transpose, the chart can be slid down by two increments until the CF chord set shows through the window 24, as shown in FIG. 2. When the music then indicates that the chord changes from C to B, the musician moves down one fret to window 29 where B is showing. Actually, he has changed from an E to an E1; chord, but he does not have to figure this out. By the use of the chart, transposition is made easier for even musicians of moderate skill.

Thus, the invention provides apparatus for the rapid change between chords often used together, and facilitates the transposition of keys. It is apparent that many details of the apparatus as shown are mere choices of detail design which can be readily altered. For example, the bar34 could be designed to press down only five strings, since the fourth string D is always depressed by the stop 36. Instead of using levers to press and lift the movable stops, buttons or other manual operating means can be used. More extensive design changes also can be resorted to, to provide the chording devices of this invention.

Further variety in chording can be obtained with another embodiment of the invention shown at 96 in FIG. 14, which enables the playing of augmented and diminished chords. The fret position for an A augmented chord is shown in FIG. 15. It is similar to the A seventh dominant chord of FIG. 10, except that an additional stop 100 is provided on the D string at the fourth fret position above a bar 34A, and the two E strings (the first and sixth strings) are damped by dampers 102 and 104 so they do not sound.

The chording apparatus 96 as shown in FIG. 14 is similar to the apparatus of FIG. 1, except that it includes a third lever 98 that can be depressed to simultaneously depress the stop 100 and the 34A, dampers 102 and 104. The stop and dampers are held on the bar 106 that can be pressed down by the lever 98. Otherwise, the apparatus is the same, having a frame 20A, a slide 21A which can be laterally shifted by the lateral spacing between strings, a bar 34A, a two-string stop 36A which shifts with the slide, and a cam-operated stop assembly with stops 38A and 40A that also shifts with the slide. The bar 106, however, does not laterally shift along with the slide 21A.

The bar 106 that supports the stop 100 and dampers 102 and 104 has an upstanding portion 108 that lies beneath the lever 98, when the slide 21A is in either of its lateral positions. Thus, although the bar 106 does not shift laterally, it can always be depressed by lever 98. A pair of springs 110 and 112 tend to bias the bar 106 upward.

The stop 100 is of hard material, so it can depress a string against the next higher fret on the guitar neck. However, the dampers 100 and 102 are of soft damping material which prevents the string from vibrating. The dampers 100 and 102 have sloping sides to tend to push the strings sideways instead of down. While the dampers limit the resulting chords to only four notes, this is generally sufficient to provide a pleasant sound for accompanyment.

As mentioned above, the chording apparatus 96 can be used to form an A augmented chord by pressing down all three levers 26A, 28A, and 98 while the frame 20A is in the A position. This forms the chord described in FIG. 15. In order to change to an E augmented chord, the frame is moved down on the fret (to the GE position) with all three levers pressed. The slide is not shifted laterally. The musician is then essentially playing a Gi augmented chord, which is identical to an E augmented chord.

The chording apparatus 96 also can be used to play an A diminished chord by performing two shifts. First, the frame 20A must be shifted up by one fret (to the A? position) and the slide must be laterally shifted (the type of shift used to change from A to E). In addition, all three levers 26A, 23A and 98 are depressed. This provides the stop configuration shown in FIG. 16. In order to form an E diminished chord from A diminished, the musician merely shifts down two fret positions (from the A position to the G 1, position). l.e., he shifts down one fret from the usual A position, shifts the slide laterally, and depresses all three levers.

The apparatus of FIG. 14, while more complex than that of FIG. 1, enables a more advanced musician to obtain chords that are suitable for almost any song that can be accompanied by chording. Its use can be mastered in a small fraction of the time it requires to learn to play the chords with the fingers, and thus provides considerable entertainment for musicians.

Although particular embodiments of the invention have been described and illustrated herein, it is recognized that modifications and variations may readily occur to those skilled in the art, an consequently, it is intended that the claims be interpreted to cover such modifications and equivalents.

We claim: 1. Apparatus for forming chords on a stringed musical instrument including a neck having frets spaced longitudinally therealong and strings spaced laterally thereacross, comprismg:

frame means slidably mounted on said neck for positioning longitudinally along said strings to different fret positions, said frame means including means for shifting said frame means laterally across said strings; and

stop means coupled to said frame means and operable between first and second lateral positions of said frame means to form first and second chords for a particular fret position of said frame means along said strings. 2. The apparatus described in claim 1 including: a slot provided on said neck and extending longitudinally therealong;

chat means slidably mounted in said slot; and p a set of chord family indications marked on said chart means at each of a plurality of fre't locations, each set denoting two chord families spaced five half-tones apart, said chart means being movable in said slot to position each of said sets of chord family indications at different fret locations.

3. The apparatus described in claim 2 wherein each set denotes: four chord families at a particular fret position along said strings; and

the chord family indications atany fret position including a first pair spaced five half-tones apart from each other and a second pair spaced five half-tones apart from each other, the first and second pairs being separated by a predetermined constant number of half-tones from each other.

4. A chording device for use on a guitar with six strings and a plurality of frets comprising:

a frame for disposition on said guitar;

a slide mounted on said frame for lateral shifting by one string; bar means mounted on said frame for depressing at least a first, second, third, fifth and sixth strings at an initial fret position;

first stop means mounted on said slide for alternately depressing the third and fourth and the fourth and fifth of said strings at a position two frets above said initial fret position in response to the lateral positioning of said slide;

second stop means mounted on said slide at a fret position one fret above said initial fret position, for movement to a position alternately adjacent to the second and third strings; and

cam means mounted on said frame means for depressing and releasing said second stop means in accordance with the lateral movement of said slide.

5. The chording device described in claim 4 including:

third stop means mounted on said slide at a fret position two frets above said initial fret positions, for movement between the same lateral positions as said second stop means;

operating means for receiving manual operating forces; and

means responsive to the operation of said operating means for alternately depressing said third stop, and lifting said third stop while depressing said second stop in accordance with the lateral movement of said slide.

6. Chording apparatus for use on a guitar comprising:

means for depressing a majority of the strings on said guitar at an initial fret position; chord changing means manually movable between first and second positions; means for depressing the second string at one fret position above said initial fret position and the third and fourth strings at twofret positions above said initial fret position when said chord changing means is in said first position, and for depressing the fourth and fifth strings at two fret positions above said first position when said chord changing means is in said second position, whereby to form two minor chords in two chord families spaced at five halftone intervals; and manually operable means responsive to the position of said chord changing means to alternately depress the second string at two fret positions above said initial fret position when said chord changing means is in said first position, and to depress a third string at one fret position above said initial fret position when said chord changing means is in said second position. v 7. The chording apparatus described in claim 6 including;

' manually operable means for altemately depressing the first and second strings at three frets above said initial fret position, at the first and second position, respectively, of said chord changing means.

8. The chording apparatus described in claim 6 including; manually operable means for depressing the fourth string at three frets above said initial fret position and damping the first and sixth strings.

9. Apparatus for forming chords on a stringed musical instrument comprising:

frame means for positioning along said strings; and stop means coupled to said frame means and operable between first said second positions to form first and.

cam means for moving said stop toward and away from the position of said strings in response to the lateral movement of said slide. 10. Apparatus for forming chords on a stringed musical instrument comprising:

frame means for positioning along said strings; and stop means coupled to said frame means and operable between first and second positions to form first and second chords which are in chord families spaced five half-tones apart, for a particular position of said frame means along said strings, said instrument havingv six strings and frets spaced along the length of said strings, said stop means comprising:

a slide movable substantially laterally between two positions spaced by approximately the lateral separation of two adjacent strings;

barring means coupled to said frame means for depressing substantially all of said strings to establish an initial fret position;

first stop means mounted on said slide for depressing two of said strings at a fret position two frets higher than said initial fret positions;

second stop means mounted on said slide for depressing one of said strings at a fret position one fret higher than said initial fret positions; and

cam means mounted on said frame means for depressing and lifting said second stop means in response to the lateral movement of said slide.

11. Apparatus for forming chords on a stringed musical instrument comprising:

frame means for positioning along said strin s; slide means mounted on said frame means or substantially lateral translation between a plurality of lateral positions; and stop means responsive to the lateral position of said slide means for depressing said strings in a plurality of fretting patterns, each of said fretting patterns defining two chords which are five half-tones apart for a predetermined position of said frame means along said strings; and stop means comprising: a multiple stop member mounted on said slide for lateral v movement therewith, said stop member having first and second longitudinally spaced end portions and first and second stops on said first and second end portions, respectively; cam means mounted on said frame means for depressing and releasing said first end portion of said stop member in response to the lateral positioning of said slide means; pivot means mounted on said frame means for engaging and releasing said second end portion of said stop member in response to the lateral position of said slide means; and manually operable pressing means for depressing said stop member at a position spaced from said pivot means. 

1. Apparatus for forming chords on a stringed musical instrument including a neck having frets spaced longitudinally therealong and strings spaced laterally thereacross, comprising: frame means slidably mounted on said neck for positioning longitudinally along said strings to different fret positions, said frame means including means for shifting said frame means laterally across said strings; and stop means coupled to said frame means and operable between first and second lateral positions of said frame means to form first and second chords for a particular fret position of said frame means along said strings.
 2. The apparatus described in claim 1 including: a slot provided on said neck and extending longitudinally therealong; chat means slidably mounted in said slot; and a set of chord family indications marked on said chart means at each of a plurality of fret locations, each set denoting two chord families spaced five half-tones apart, said chart means being movable in said slot to position each of said sets of chord family indications at different fret locations.
 3. The apparatus described in claim 2 wherein each set denotes: four chord families at a particular fret position along said strings; and the chord family indications at any fret position including a first pair spaced five half-tones apart from each other and a second pair spaced five half-tones apart from each other, the first and second pairs being separated by a predetermined constant number of half-tones from each other.
 4. A chording device for use on a guitar with six strings and a plurality of frets comprising: a frame for disposition on said guitar; a slide mounted on said frame for lateral shifting by one string; bar means mounted on said frame for depressing at least a first, second, third, fifth and sixth strings at an initial fret position; first stop means mounted on said slide for alternately depressing the third and fourth and the fourth and fifth of said strings at a position two frets above said initial fret position in response to the lateral positioning of said slide; second stop means mounted on said slide at a fret position one fret above said initial fret position, for movement to a position alternately adjacent to the second and third strings; and cam means mounted on said frame means for depressing and releasing said second stop means in accordance with the lateral movement of said slide.
 5. The chording device described in claim 4 including: third stop means mounted on said slide at a fret position two frets above said initial fret positions, for movement between the same lateral positions as said second stop means; operating means for receiving manual operating forces; and means responsive to the operation of said operating means for alternately depressing said third stop, and lifting said third stop while depressing said second stop in accordance with the lateral movement of said slide.
 6. Chording apparatus for use on a guitar comprising: means for depressing a majority of the strings on said guitar at an initial fret position; chord changing means manually movable between first and second positions; means for depressing the second string at one fret position above said initial fret position and the third and fourth strings at two fret positions above said initial fret position when said chord changing means is in said first position, and for depressing the fourth and fifth strings at two fret positions above said first position when said chord changing means is in said second position, whereby to form two minor chords in two chord families spaced at five half-tone intervals; and manually operable means responsive to the position of said chord changing means to alternately depress the second string at two fret positions above said initial fret position when said chord changing means is in said first position, and to depress a third string at one fret position above said initial fret position when said chord changing means is in said second position.
 7. The chording apparatus described in claim 6 including; manually operable means for alternately depressing the first and second strings at three frets above said initial fret position, at the first and second position, respectively, of said chord changing means.
 8. The chording apparatus described in claim 6 including; manually operable means for depressing the fourth string at three frets above said initial fret position and damping the first and sixth strings.
 9. Apparatus for forming chords on a stringed musical instrument comprising: frame means for positioning along said strings; and stop means coupled to said frame means and operable between first said second positions to form first and second chords which are in chord families spaced five half-tones apart, for a particular position of said frame means along said strings, said stop means comprising: a slide movable between two substantially laterally spaced positions with respect to said frame means; a stop mounted on said slide for lateral movement with it, said stop movable toward and away from the position of said strings; and cam means for moving said stop toward and away from the position of said strings in response to the lateral movement of said slide.
 10. Apparatus for forming chords on a stringed musical instrument comprising: frame means for positioning along said strings; and stop means coupled to said frame means and operable between first and second positions to form first and second chords which are in chord families spaced five half-tones apart, for a particular position of said frame means along said strings, said instrument having six strings and frets spaced along the length of said strings, said stop means comprising: a slide movable substantially laterally between two positions spaced by approximately the lateral separation of two adjacent strings; barring means coupled to said frame means for depressing substantially all of said strings to establish an initial fret position; first stop means mounted on said slide for depressing two of said strings at a fret position two frets higher than said initial fret positions; second stop means mounted on said slide for depressing one of said strings at a fret position one fret higher than said initial fret positions; and cam means mounted on said frame means for depressing and lifting said second stop means in response to the lateral movement of said slide.
 11. Apparatus for forming chords on a stringed musical instrument comprising: frame means for positioning along said strings; slide means mounted on said frame means for substantially lateral translation between a plurality of lateral positions; and stop means responsive to the lateral position of said slide means for depressing said strings in a plurality of fretting patterns, each of said fretting patterns defining two chords which are five half-tones apart for a predetermined position of said frame means along said strings; and stop means comprising: a multiple stop member mounted on said slide for lateral movement therewith, said stop member having first and second longitudinally spaced end portions and first and second stops on said first and second end portions, respectively; cam means mounted on said frame means for depressing and releasing said first end portion of said stop member in response to the lateral positioning of said slide means; pivot means mounted on said frame means for engaging and releasing said second end portion of said stop member in response to the lateral position of said slide means; and manually operable pressing means for depressing said stop member at a position spaced from said pivot means. 